Signal processing unit with serial time multiplex connections between signal processing and control means

ABSTRACT

The invention relates to a signal processing unit, in particular for a telecommunication system, comprising means for digital signal processing, means for storage of data and control means, whereby the means for digital signal processing and the control means are connected to each other by means of serial time multiplex connections. A signal processing unit with particularly wide applications, in particular for signal processing tasks in digital communication systems, is thus achieved.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/EP03/03039, filed Mar. 24, 2003 and claims the benefit thereof.The International Application claims the benefits of Europeanapplication No. 012007908.3 filed Apr. 9, 2002, both of the applicationsare incorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a signal processing unit, in particular for atelecommunication system, comprising means for digital signalprocessing, means for storage of data and control means.

BACKGROUND OF INVENTION

Modern digital telecommunication systems must handle a range of signalprocessing tasks. These tasks include echo compensation, dial pulseidentification and dial tone identification, as well as voicerecognition, voice storage, voice compression and voice synthesis inconnection with automatic information systems.

Due to the high computational effort—to be expended in real time—whichis associated with this multitude of signal processing tasks, such taskshave hitherto been handled using function-specific modules. Inparticular, the retrofitting of network elements with thesefunctionalities is a logistically intensive task.

SUMMARY OF INVENTION

The object of the invention, therefore, is to provide a signalprocessing unit of the type mentioned in the introduction, which can beused for various digital signal processing tasks.

This object is achieved according to the invention by a signalprocessing unit in which the means for digital signal processing and thecontrol means are connected to each other by means of serial timemultiplex connections. The signal processing unit according to theinvention can be used to resolve all the usual signal processing tasksto be carried out, such as echo compensation, dial pulse identificationand dial tone identification, as well as voice recognition, voicestorage, and voice synthesis in connection with automatic informationsystems.

It is advantageous if the serial time multiplex connections areimplemented as a PCM 30 system. The PCM 30 system is a digitaltransmission system that allows the simultaneous transmission of up to32 voice channels. This system is internationally standardized (exceptfor the U.S.A. where the number of voice channels is 24) and forms thebasis for all digital transmission systems with a higher number ofchannels.

Ideally, digital signal processors and/or echo suppression means areprovided as means for digital signal processing. These are standarddigital signal processing elements, which are suitably designed forthese tasks, are available in large quantities, and are relativelyinexpensive.

Furthermore, an embodiment in which the signal processing unit isimplemented as a separate module is advantageous as this makes thesignal processing unit very easy to integrate into systems.

In a particularly advantageous application, the signal processing unitis implemented as a separate module of an exchange of a digitalswitching system.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail with the help of diagrams.In, these, by way of example,

FIG. 1 shows the integration of a signal processing unit according tothe invention into an exchange of a telecommunication network,

FIG. 2 shows the configuration of a signal processing unit according tothe invention,

FIG. 3 is a detailed diagram showing the time multiplexing connectionsaccording to the invention, and

FIG. 4 is a diagram showing the external interfaces of the signalprocessing unit.

DETAILED DESCRIPTION OF INVENTION

The signal processing unit VPU shown in FIG. 1 is a module which isplugged into slots of a trunk group UI-LTGN (also UI-LTGP) of a digitalswitching system, such as—for example—the EWSD digital electronicswitching system from Siemens. The trunk groups form the interfacebetween the subscriber lines and the switching network SN. As well as upto 4 signal processing units according to the invention, each trunkgroup UI-LTGN contains a group processor GP as the central control unit.

The construction of an inventive signal processing unit for the SiemensEWSD system is explained in greater detail with the help of FIG. 2. Thissignal processing unit incorporates as modules the power supply unit SV,main memory S, supervisory unit Ü, interface driver for Ethernet andV.24 ports, a clock supply TS, a control unit for the time multiplexconnections PCM, module control unit BC, signal processors SP1, SP2, SP3and an echo suppression unit EC.

The functional elements of the signal processing unit VPU are connectedby means of a data bus Dbus, address bus Abus, time multiplexconnections PCM clock&sync and PCM highway, and other control andsignaling lines Others.

The power supply unit SV is based on a DC/DC converter unit, whichconverts the voltage of −48/−60 V which is present in the system, to thevoltage of 3.3 V which is required by components of the signalprocessing unit VPU.

The supervisory unit Ü guarantees a defined startup of the signalprocessing unit VPU when the supply voltage is applied. It alsosupervises the level of the supply voltage and delivers a warning signalif the permitted values are not reached. The supervisory unit Ü can alsobe used for restarting the signal processing unit VPU during operationif necessary.

The Internet driver for Ethernet EN as per IEEE 802.3 is implementedwith a “Fast Ethernet Controller” of type MPC860T from Motorola. TheEthernet interface of the signal processing unit VPU is primarily usedfor loading control programs for the function elements.

The RS232 port V.24 of the signal processing unit VPU, which iscontrolled by the processor of the module control unit BC, is usedmainly for the tasks of error detection and monitoring (debugging andtracing).

Further user interfaces are provided for control purposes on the signalprocessing unit VPU, namely a JTAG interface for programming and LEDsfor displaying the operating status.

The signals necessary for operating the signal processing unit VPU arederived from clocks in the trunk group by means of the clock supply TS.

The interaction of all function elements of the signal processing unitVPU is managed by means of the module control unit BC. The modulecontrol unit BC is implemented in the exemplary embodiment with aprocessor of the type “PowerQUICCprocessor MPC860T” from Motorola.

A permanent memory, which is implemented by means of EEPROMs, isprovided for storing module-specific data. A microcontroller forcontrolling the startup of the processor is implemented in an additionalpermanent memory which is constructed from ROM or Flash storageelements.

32 Mbytes of SDRAM are provided as main memory for the processor.

Digital signal processors of type TMS320C6201 from Texas Instruments areused as signal processors SP1, SP2, SP3; these are equipped with DRAM orSDRAM storage elements each with a minimum storage capacity of 32Mbytes.

The echo suppression unit EC is equipped so as to permit echosuppression up to a delay of 64 ms for all receive channels of the timemultiplex connections. The echo suppression unit EC is controlled by themodule control unit BC.

The signal processors are each connected via their host port interfaceto the module control unit, and via serial interfaces to the timemultiplex connections PCM.

In addition to the storage elements of the individual function elements,a main memory S is provided which is implemented by means of Flashmemory elements and incorporates up to 256 Mbytes of storage capacity.

The control unit for the time multiplex connections PCM is explained ingreater detail with the help of FIG. 3.

This shows, by way of example, a detailed representation of the timemultiplex connections, according to the invention, between the functionelements of the signal processing unit VPU: module control unit BC,signal processors SP1, SP2, SP3, echo suppression unit EC, and theinterfaces SIHO, SIHIM, SPHI2 . . . SPHI6, and SPHO2 . . . SPHO6, whichare predefined through the integration of the signal processing unit VPUinto a trunk group UI-LTGN of a digital switching system.

These time multiplex connections are designed as PCM 30 connections with32 telephone channels (SPHx) or 32 signal channels (SIHx).

The signaling channels of the time multiplex connections PCM areconducted directly via the signaling interface SIHO, SIHIM to a serialinterface of the module control unit BS and via a further interface ofthe module control unit BS to control inputs of the driver elements ofthe telephone interfaces SPHI2 . . . SPHI6, and SPHO2 . . . SPHO6 of thesignal processing unit VPU.

The signal processing unit VPU is connected to the telephone channels ofthe trunk group UI-LTGN of a digital switching system via the telephoneinterfaces SPHI2 . . . SPHI6, and SPHO2 . . . SPHO6. The telephonechannels are conducted internally to interfaces of the signal processorsSP1, SP2, SP3 and of the echo suppression unit EC.

This also means that unused channels of the time multiplex connectionsPCM, which are provided per se for telephone traffic, can be used fordata exchange between the signal processors SP1, SP2, SP3.

By means of the embodiment described above, the signal processing unitVPU can now easily be adapted to each signal processing task byprogramming its function elements accordingly. In particular, theinternal continuation of time multiplex connections PCM facilitates theefficient processing and forwarding of telephone data, thus enabling themost diverse requirements to be processed in real time.

Thus the system processing unit VPU could also conceivably be used as avoiceover IP gateway, i.e. as the interface between a conventional timemultiplex telephone system and a computer network.

The task of such a gateway is to convert compressed voice data that hasbeen transferred over a computer network, packet by packet, into pulsecode-modulated voice data (PCM 30), and vice-versa. This gateway istherefore a complex network element and requires correspondinglyefficient hardware and software. These demanding requirements arefulfilled by the signal processing unit thanks to its structureaccording to the invention.

1.-5. (canceled)
 6. A signal processing unit, comprising: a mechanismfor digital signal processing; and a control mechanism, wherein themechanism for digital signal processing and the control mechanism areconnected by a serial time multiplex connection.
 7. The signalprocessing unit according to claim 6, wherein the signal processing unitis used in a telecommunication system.
 8. The signal processing unitaccording to claim 6, further comprising a mechanism for storing data.9. The signal processing unit according to claim 6, wherein the serialtime multiplex connection is implemented as a PCM 30 system.
 10. Thesignal processing unit according to claim 7, wherein the serial timemultiplex connection is implemented as a PCM 30 system.
 11. The signalprocessing unit according to claim 8, wherein the serial time multiplexconnection is implemented as a PCM 30 system.
 12. The signal processingunit according to claim 6, wherein the mechanism for digital signalprocessing is a digital signal processor and/or a mechanism for echosuppression.
 13. The signal processing unit according to claim 7,wherein the mechanism for digital signal processing is a digital signalprocessor and/or a mechanism for echo suppression.
 14. The signalprocessing unit according to claim 8, wherein the mechanism for digitalsignal processing is a digital signal processor and/or a mechanism forecho suppression.
 15. The signal processing unit according to claim 9,wherein the mechanism for digital signal processing is a digital signalprocessor and/or a mechanism for echo suppression.
 16. The signalprocessing unit according to claim 6, wherein the signal processing unitis implemented as a separate module.
 17. The signal processing unitaccording to claim 7, wherein the signal processing unit is implementedas a separate module.
 18. The signal processing unit according to claim8, wherein the signal processing unit is implemented as a separatemodule.
 19. The signal processing unit according to claim 9, wherein thesignal processing unit is implemented as a separate module.
 20. Thesignal processing unit according to claim 12, wherein the signalprocessing unit is implemented as a separate module.
 21. The signalprocessing unit according to claim 16, wherein the signal processingunit is implemented as a separate module of an exchange of a digitalswitching system.